A digital pen gives us a lot of flexibility to access a variety of functionalities in a software program, but may lose some of the naturalness of using various specialized physical tools (pen, painting-brush, sketching pencil, knife, compasses...). By augmenting the digital pen with a multi-touch sensor and an orientation sensor, we can recognize how the pen is held by the user. Exactly like how people hold different physical tools differently, the user can now switch the grip on the digital pen to naturally switch between different virtual tools.